Survey of molluscs in killai backwaters of South India

Assess the distribution of molluscs in mangrove forest of Killai bactwarters in Tamil Nadu, south India. Three different sampling sites based on salinity variation were selected. During the study period eighteen species of molluscs including nine species of gastropods and 9 species bivalves were observed. The gastropod Cerithidea cingulata and the bivalve Crossostrea madrasensis was absent in fresh water zone, but rich in marine zone. The gastropod (Pythia plicata) was absent in marine zone, but rich in freshwater zone in arboreal habitat was found only few collections. The Pythia plicata found in few mangrove plants (Avicennia marina, Excoecaria agallocha, Avicennia officinalis and Acanthus ilicifolius). Maximum number of individuals (52) of Pythia plicata were observed in Avicennia officinalis at 225 cm height and 21 number of individuals were found at 125 - 150 cm height. The another gastropods Nassarius stolatus were also found from Avicennia marina and Acanthus ilicifolis plants at the height of 0 - 25 cm in mangrove rich zone. The maximum number of Cerethidea cingulata (97 numbers per 25 square centimeters) was reported in marine zone.